[FMFP] Fix error from comments

semester4/fmfp/parts/04_language-semantics/01_operational-semantics/00_big-step-semantics/01_semantics.tex

@@ -26,7 +26,7 @@
     \end{prooftree}
     \qquad
     \begin{prooftree}
-        \hypo{\langle s, \sigma \rangle \rightarrow \sigma'}
+        \hypo{\langle s', \sigma \rangle \rightarrow \sigma'}
         \infer1[\textsc{IfF}$_{NS}$]{\langle \texttt{if}\; b \; \texttt{then} \; s \; \texttt{else} \; s' \; \texttt{end}, \sigma \rangle \rightarrow \sigma'}
     \end{prooftree}
 \]